German army traditionally stressed the personal factor and therefore the importance of the second command task, selecting the right men. Operated the ‘seniority tempered by merit’ principle for appointing and promoting officers, based on a carefully structured though flawed confidential reporting system. Continuous but not always successful efforts during the war to select good and weed out unsuitable commanders and general staff officers. Limits on ability to post officers freely, especially because of the constraints on and conservatism of the Military Cabinet running the system. Suggestions that function automatically overrode rank at best oversimplified. Always the possibility of friction in such cases, illustrating the effect of personal factors such as reputation, honour, ambition, pay and strain. Personal relationships, sometimes developing into networks and cliques, interacted with objective professional considerations and influenced the conduct of operations as well as the subsequent historiography. Two case studies illustrate these factors.